Control of microorganisms in food plants is required to ensure the safety of the food being processed. The Hazard Analysis and Critical Control Points (HACCP) system is a food processing control system that seeks to prevent food safety problems. Using a HACCP plan, a company analyzes its processes to identify areas of risk and concentrates its monitoring and prevention resources at those critical points. In particular, predetermined actions must be available to correct the processes if a control point goes beyond its predetermined limits. HACCP plans became mandatory for federally inspected U.S. meat and poultry plants beginning in 1998. More recently, the Food Safety and Inspection Service (FSIS) has issued new “science based” HACCP regulations, together with accompanying Sanitation Standard Operating Procedures (SSOPs) and Good Manufacturing Practices (GMPs), which are designed to encourage companies to monitor and prevent the microbiological contamination of foods during processing. “Science based” sanitation quantification means that a level of microbiological contamination, for example the amount of pathogenic bacteria present during food processing, is quantified with much greater accuracy as compared to “non-science based” sanitation quantification, such as visual inspection of food equipment. Visual inspection of equipment surfaces is not sufficient to determine the cleanliness of equipment if the hazard being measured is bacterial. “Science based” quantification of sanitation procedures, however, is extremely difficult, and is currently based primarily on expensive, non-representative microbial sampling methods.
Typically, food processing equipment, such as freezers and ovens, are periodically scheduled for cleaning and then sanitizing with chemicals. Quantification of the efficacy of chemical sanitizing is normally not possible in an industrial setting. The variability of coverage of chemicals, contact times, starting numbers of bacteria, and other factors affecting the action of cleaning chemicals against bacteria are too great to make quantification of efficacy possible on the large scale required in food processing plants. Thus, to quantify a sanitation level of the food processing equipment that has undergone chemical sanitizing, expensive, non-representative microbial sampling must be conducted, as discussed above.
An alternative approach to chemical sanitizing is sanitizing through thermal destruction of bacteria. Steam in particular, if applied correctly to large pieces of equipment, can be effective in killing bacteria in a uniform and predictable manner. For example, U.S. Pat. No. 6,264,889B1 describes an apparatus and method for microbial intervention and pasteurization of food processing equipment using steam. The method applies steam to food items or food processing equipment so as to raise the surface temperature of food items or food processing equipment. Once the surface temperature rises to a certain temperature, for example 74° C., the temperature is maintained at that level for a certain period of time, for example, 60 seconds. After that, chilled water at about 2–5° C. is sprayed onto the food items or food processing equipment. It is claimed that alternating heating and cooling of the food items or food processing equipment can provide a five log reduction (100,000 times) in the amount of microbial pathogens on the surfaces of food items or food processing equipment. This method, however, is not capable of continuously monitoring the sanitation level in food processing equipment throughout its use, including those times when the equipment is in normal use and is not being sanitized. In other words, while the method is directed to achieving a certain sanitation level immediately after sanitizing, it is silent as to how to monitor and control sanitation level of food processing equipment during its normal use, especially after some time has lapsed since its last sanitizing.
In reality, however, bacteria on the surfaces of food processing equipment can grow (or die) over time. Thus, while procedures that help determine (and/or control) the number of bacteria on some area of food processing equipment at a single point in time can be helpful, these procedures do not address the fact that bacterial levels are changing continuously. A more thorough approach would require continuous monitoring of the sanitation level of any equipment at all times, not just during or right after sanitizing. Therefore, a need exists for a method and system for continuously monitoring and controlling the sanitation level in food processing equipment.